Book/Report

FZJ-2018-04248

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png A microscopic model for correlated 2 pi exchange model in free nucleon-nucleon scattering and in nuclear matter

Kim, H.-C. (Corresponding author)FZJ*

1993
Forschungszentrum Jülich GmbH Zentralbibliothek Verlag Jülich

Please use a persistent id in citations: http://hdl.handle.net/2128/19371

Report No.: Juel-2771

Abstract: A microscopic model for the N$\overline{N} \rightarrow \pi \pi$ amplitude has been constructed based on nucleon and delta-isobar exchange, which in the pseudophysical region (4m$_{\pi^2} \le$ t $\le$ 50m$_{\pi ^2}$) roughly agrees with information obtained by analytic continuation of empirical $\pi$N and $\pi \pi$ data. Starting from these amplitudes, the correlated 2$\pi$ exchange contribution to the NN interaction has been derived using dispersion theoretic methods. It turns out that, in high partial waves, this contribution is considerably larger (by about 20%) compared to the effective $\sigma$- and $\rho$-exchange used in the full Bonn potential. As a consequence, it turned out that a quantitative description of high NN partial wave phase shifts definitely favors a somewhat smaller rNN coupling constant, in agreement with recent findings in an empirical analysis by the Nijmegen group. The prediction of low NN partial wave phase shifts has been presented, being compared with empirical NN data. In addition to free NN scattering, medium modifications of the $\sigma$ channel in the NN potential have been studied. These modifications arise from a change in the $\pi \pi$ rescattering through the in-matter pion dispersion relation. We also have considered the possibility of dropping meson masses as suggested by QCD sum rules.

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Contributing Institute(s):

1. Publikationen vor 2000 (PRE-2000)

Research Program(s):

1. 899 - ohne Topic (POF3-899) (POF3-899)

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